# 2021 Boston Red Sox season

The 2021 Boston Red Sox season was the 121st season in the team's history, and their 110th season at Fenway Park. The team entered the offseason conducting a managerial search, after declining to bring back Ron Roenicke from the shortened 2020 season. On November 6, 2020, the team re-hired Alex Cora as manager; Cora had skippered the Red Sox in 2018 and 2019, then sat out 2020 serving a one-year suspension for his role in the Houston Astros sign stealing scandal in 2017.
This was the Red Sox' first season since 2019 with fans at Fenway Park, with a limited capacity of approximately 4,500 to start the season due to the ongoing COVID-19 pandemic. The capacity was increased to approximately 9,400 for games after May 10. Fenway returned to full capacity starting May 29, with an announced attendance of 25,089 at that day's game. The first home sellout of the season was the June 25 game against the New York Yankees, with an announced attendance of 36,869.
On June 4–6, the Red Sox swept a three-game series against the rival Yankees at Yankee Stadium for the first time since June 2011. On June 13, the Toronto Blue Jays set a single-game record for home runs by a visiting team at Fenway Park, with eight. In early July, the Red Sox led MLB with five players selected to the All-Star Game. Beginning in late August, the team had a spate of positive COVID-19 testing, resulting in more than 10 players being placed on the COVID-related injured list.
The Red Sox finished the regular season with a 92–70 record and qualified for the postseason as the fourth seed in the American League (AL), defeating the fifth-seed Yankees in the AL Wild Card Game at Fenway Park on October 5. They then defeated the Tampa Bay Rays in the AL Division Series, 3–1 games. The Red Sox lost to the Houston Astros in the best-of-seven AL Championship Series in six games.

## Offseason

The Red Sox entered the offseason with the manager position vacant, as prior to the team's final game of the 2020 season, the team announced that Ron Roenicke would not be retained.
The Red Sox also entered the offseason with six guaranteed player contracts for 2021, totaling slightly more than $115 million: Chris Sale ($25.60 million), Xander Bogaerts ($20 million), J. D. Martinez ($19.375 million), Nathan Eovaldi ($16.88 million); Dustin Pedroia ($13.3 million), and Christian Vázquez ($4.52 million).

### Spring training

"Truck Day", when the team's equipment departs Fenway Park for spring training in Florida, was February 8. Pitchers and catchers began workouts at JetBlue Park in Fort Myers on February 18; full squad workouts began on February 22.
The team had been scheduled to begin preseason games on February 26, with an exhibition against the Northeastern Huskies, but that contest was canceled. The team began Grapefruit League games on February 28, losing to the Minnesota Twins. Announcers for spring training games broadcast on NESN were Dave O'Brien and Tom Caron for play-by-play with Jerry Remy, Dennis Eckersley and Lenny DiNardo for color commentary. Boston's spring training games continued through March 30; the team compiled a 16–11 record, scoring 159 runs while allowing 131.

## Regular season

Major League Baseball announced the 2021 regular season schedule on July 9, 2020. The Red Sox' schedule, as originally released, spanned April 1 to October 3. The All-Star Game was scheduled for July 13. For interleague play, the Red Sox were scheduled to face National League East teams.

### Opening Day lineup

Originally scheduled for April 1, the team's first game of the season—at Fenway Park against the Baltimore Orioles—was postponed to April 2, due to rain.
| Order | No. | Player | Pos. |
| 1 | 5 | Kiké Hernández | 2B |
| 2 | 99 | Alex Verdugo | CF |
| 3 | 28 | J. D. Martinez | DH |
| 4 | 2 | Xander Bogaerts | SS |
| 5 | 11 | Rafael Devers | 3B |
| 6 | 10 | Hunter Renfroe | RF |
| 7 | 12 | Marwin González | LF |
| 8 | 7 | Christian Vázquez | C |
| 9 | 29 | Bobby Dalbec | 1B |
| — | 17 | Nathan Eovaldi | P |
Source:
July :
July
The Red Sox entered July atop the American League East with a record of 50–31, having just won the first three games of a four-game series against the Royals.
July 1, vs. Kansas City Royals (cont'd)
The Red Sox' winning streak reached seven games as the team completed a four-game sweep of the Royals with a 15–1 win. Starter Nathan Eovaldi held Kansas City scoreless through seven innings, followed by reliever Matt Andriese who pitched the final two innings and allowed only an unearned run. Each Boston starter had at least one hit. Kiké Hernández, J. D. Martinez, Danny Santana, and Rafael Devers each homered.
Red Sox won the series 4–0 (34–14 runs)
July 2–July 4, at Oakland Athletics
The opener of a three-game road series in Oakland was a 3–2 extra innings win for Boston, extending the winning streak to eight games. Kiké Hernández drove in the winning run in the top of the 10th, with Adam Ottavino holding the Athletics scoreless in the bottom of the inning for the save. Closer Matt Barnes, who blew a save in the bottom of the ninth, was credited with the win. Starter Eduardo Rodríguez allowed no runs and only a single hit in six innings, but had to settle for a no decision. The second game of the series also went to extra innings, tied 4–4. After Boston starter Garrett Richards held Oakland to two runs on five hits in five innings, the Athletics tied the game in the eighth inning via two runs off of reliever Yacksel Ríos. J. D. Martinez, playing left field, threw out Athletics catcher Sean Murphy at the plate in the bottom of the 10th inning, preserving the tie. After a scoreless 11th inning, the Red Sox scored twice in the top of the 12th to take a 6–4 lead. However, Oakland scored three runs off of Matt Andriese in the bottom of the inning for a 7–6 win. Hernández hit his 10th home run of the season. The final game of the series was a 1–0 Boston win, with the only run of the game coming on a double–single–ground-out sequence in the sixth inning. Alex Verdugo scored the run, and was the only player in the game with more than one hit. Starter Nick Pivetta allowed just two hits in seven innings for the win, while Barnes earned his 19th save of the season.
Red Sox won the series 2–1 (10–9 runs)
July 5–July 7, at Los Angeles Angels
The first game of a three-game series with the Angels was won by the Red Sox, 5–4. Starter Martín Pérez got the win, having held Los Angeles to one run on eight hits in 5+1⁄3 innings. Adam Ottavino notched his seventh save of the season. Rafael Devers had three hits, include a home run; Christian Arroyo also homered. The Angels won the second game of the series, 5–3, with all their runs scored off of starter Nathan Eovaldi, who lasted 5+2⁄3 innings and took the loss. Hunter Renfroe homered. The final game of the series was a 5–4 Angels win, dropping starter Eduardo Rodríguez to a 6–5 record for the season. Xander Bogaerts went 3-for-4 at the plate.
Red Sox lost the series 1–2 (12–14 runs)
July 9–July 11, vs. Philadelphia Phillies
Boston won the opener of a three-game home series against the Phillies, 11–5. Starter Garrett Richards got the win, improving to 5–5 on the season. Six different Red Sox batters had two hits apiece, while J. D. Martinez, Kiké Hernández, and Rafael Devers each homered. The Phillies won the second game of the series, 11–2. Holding a 3–2 lead after seven innings, Philadelphia scored eight runs in the top of the eighth inning to put the game out of reach. Starter Martín Pérez allowed three runs on six hits, exiting after 3+2⁄3 innings and taking the loss. Xander Bogaerts hit his 14th home run of the season. The final game of the series was another Phillies win, 5–4. Starter Nick Pivetta took the loss against his former team, allowing five runs on four hits in four innings. Bogaerts homered again. The Red Sox reached the All-Star break atop the American League East with a record of 55–36, 1+1⁄2 games ahead of Tampa Bay.
Red Sox lost the series 1–2 (17–21 runs)
July 13, All-Star Game at Coors Field
The Red Sox had five players selected to the All-Star Game; all five played as the American League defeated the National League, 5–2. Xander Bogaerts and Rafael Devers started the game at shortstop and third base, respectively. Bogaerts went 2-for-3 at the plate with an RBI, while Devers went 1-for-2. They were replaced by reserve players in the bottom of the fifth inning. Nathan Eovaldi pitched the fourth inning, allowing no runs on one hit. J. D. Martinez entered the game as designated hitter in the top of the fifth inning and went 0-for-2. Matt Barnes pitched the eighth inning, allowing no runs on two hits and a walk.
July 15–July 18, at New York Yankees
The opener of a four-game series at Yankee Stadium was postponed due to three positive COVID-19 test results within the Yankees' pitching staff. The next day, Boston won the first game played in the series, 4–0. Starter Eduardo Rodríguez allowed only two hits in 5+2⁄3 innings and earned the win. Tanner Houck pitched the final three innings, earning a save. Christian Arroyo and J. D. Martinez each homered. The Yankees won the second game of the series, 3–1, in a six-inning rain-shortened contest. Starter Nathan Eovaldi held the Yankees to one run on two hits in five innings, leaving with a no decision. Reliever Hirokazu Sawamura allowed two home runs in the bottom of the sixth, and took the loss. The game included the MLB debut of Jarren Duran, the ejections of bench coach Will Venable and backup catcher Kevin Plawecki following a check-swing third-strike call that the Red Sox dugout took exception to, and a brief stoppage in play after left fielder Alex Verdugo was struck in the back by a baseball thrown by a fan. The final game of the series was a 9–1 New York win, as starter Martín Pérez allowed three runs on five hits in four innings, taking the loss. Xander Bogaerts was the only Red Sox batter with two hits, while Hunter Renfroe had the only RBI.
Red Sox lost the series 1–2 (6–12 runs)
July 19–July 21, at Toronto Blue Jays (in Buffalo)
Boston won the first game of a three-game series played in Buffalo, New York, 13–4. J. D. Martinez was 4-for-4 with a walk, while Kiké Hernández hit two home runs. Boston also had home runs from Jarren Duran, Hunter Renfroe (a grand slam), Rafael Devers, and Danny Santana. Starter Nick Pivetta allowed four runs on 11 hits in 6+2⁄3 innings and earned the win. The second game of the series was rained out, with a makeup game scheduled for August 7. Boston won the final game of the series, 7–4. Starter Garrett Richards earned the win, allowing four runs on four hits in 5+2⁄3 innings, and Matt Barnes earned his 20th save of the season. Hernández, Devers, Martinez, Renfroe, and Michael Chavis each homered.
Red Sox won the series 2–0 (20–8 runs)
July 22–July 25, vs. New York Yankees
The first game of a four-game home series against the Yankees was a 5–4 extra-innings win. Starter Tanner Houck left after 4+2⁄3 innings due to a 55 minute rain delay, having held New York to one unearned run on two hits. Trailing 3–1 entering the bottom of the ninth, Kiké Hernández drove in two runs via a two-out double to tie the game. The Yankees scored one run off of Matt Barnes in the top of the 10th. In the bottom of the inning, Boston scored twice, taking advantage of four wild pitches by Yankees reliever Brooks Kriske; Hunter Renfroe drove in the winning run via a sacrifice fly. The second game of the series was a 6–2 Boston win. Trailing 1–0 entering the bottom of the fifth, the Red Sox scored three runs, then added three more in the bottom of the seventh. Rafael Devers had five RBIs via two home runs. Starter Eduardo Rodríguez left in the second inning due to migraine symptoms. Yacksel Ríos, the third of five Boston relievers who followed Rodríguez, allowed no runs or hits in two innings of work and got the win. In the second game of the series, Boston took an early 3–0 lead, but the Yankees scored four unanswered runs in the eighth inning to give the Red Sox a 4–3 defeat. Starter Nathan Eovaldi lasted 7+2⁄3 innings and allowed two runs on seven hits; reliever Adam Ottavino allowed two runs on three hits in 1⁄3 of an inning and took the loss. Kevin Plawecki was the only Boston batter with two hits. The final game of the series was a 5–4 Red Sox win. Entering the bottom of the eighth inning, Boston had not recorded a hit and trailed, 4–0. Five consecutive hits and a sacrifice fly put the Red Sox ahead by a run. Barnes then closed out the game for his 21st save of the season. The win went to Brandon Workman, the third of four relievers who followed starter Martín Pérez.
Red Sox won the series 3–1 (19–14 runs)
July 26–July 29, vs. Toronto Blue Jays
The Red Sox won the first game of a four-game home series against Toronto, 5–4. Boston's 3–2 fifth-inning lead became a 4–3 deficit via a two-run Bo Bichette homer. Alex Verdugo's own two-run homer in the eighth inning put Boston back in the lead, allowing Matt Barnes to close out the game with his 22nd save of the year. Starter Nick Pivetta had a no decision after allowing four runs on six hits in 4+2⁄3 innings; reliever Adam Ottavino got the win. Rafael Devers also homered. The second game of the series was postponed due to rain, resulting in a doubleheader being scheduled for the following day. The first game of the doubleheader was won by the Blue Jays, 4–1, in seven innings. Starter Garrett Richards allowed four runs on eight hits in four innings and took the loss. J. D. Martinez drove in Boston's only run. The second game of the doubleheader was a Boston win, also by a 4–1 score in seven innings. Starter Tanner Houck allowed one run in four innings; the win went to reliever Garrett Whitlock, who pitched two scoreless innings, while Barnes registered another save. Kevin Plawecki had three hits, and Jarren Duran had two RBIs. The final game of the series was a 13–1 Blue Jays win, with starter Eduardo Rodríguez taking the loss after allowing six runs in 3+1⁄3 innings. Bobby Dalbec drove in Boston's only run. Red Sox backup catcher Plawecki pitched a scoreless ninth inning.
Red Sox split the series 2–2 (11–22 runs)
July 30–July 31, at Tampa Bay Rays
Tampa Bay won the opener of a three-game series, 7–3, dropping starter Martín Pérez to a 7–7 record for the season. The second game of the series was also won by the Rays, 9–5. Starter Nathan Eovaldi allowed six runs (five earned) on six hits in 5+1⁄3 innings and took the loss. Xander Bogaerts and Bobby Dalbec each homered. The Rays ended July back in the lead of the American League East with a 63–42 record, one-half game ahead of the Red Sox at 63–43. :
This was the eighth time for the Red Sox to qualify for the postseason as a wild card team since the expansion of the MLB postseason in 1994, and the first time since 2009.

## Postseason
### American League Wild Card Game vs. New York Yankees

The Red Sox entered the Wild Card Game as the fourth seed in the American League, hosting the fifth-seeded Yankees. Nathan Eovaldi and Gerrit Cole were the starting pitchers, respectively. J. D. Martinez, who injured his ankle in the final game of the regular season, was not included on Boston's roster for the game.
Boston took an early 2–0 lead, via a two-run homer by Xander Bogaerts in the first inning. A solo home run by Kyle Schwarber in the third inning extended the lead to 3–0. Cole left without recording an out in the third, having allowed three runs on four hits; he was replaced by Clay Holmes. A solo home run by Anthony Rizzo in the top of the sixth made it a 3–1 game. Eovaldi left with one out in the sixth; he was replaced by Ryan Brasier. A New York rally was snuffed out when Aaron Judge was thrown out at the plate attempting to score from first on a Giancarlo Stanton single off of the Green Monster. Alex Verdugo's RBI double in the bottom of the sixth put Boston ahead by three again, 4–1. Verdugo drove in another two runs in the seventh, extending Boston's lead to 6–1. Stanton homered with one out in the ninth, but the Yankees could not rally further as the Red Sox won, 6–2.
Red Sox won the series 1–0 (6–2 runs)

### American League Division Series vs. Tampa Bay Rays

This was the third postseason matchup between the Red Sox and Rays. Their previous postseason meetings were in the 2008 ALCS, won by the Rays in seven games, and in the 2013 ALDS, won by the Red Sox in four games.
ALDS Results :
| Game | Date | Day | Result | Location | Television | Series |
| 1 | October 7 | Thursday | Red Sox 0, Rays 5 | Tropicana Field | Fox Sports 1 | Rays, 1–0 |
| 2 | October 8 | Friday | Red Sox 14, Rays 6 | Tropicana Field | Fox Sports 1 | tied, 1–1 |
| 3 | October 10 | Sunday | Rays 4, Red Sox 6 (13) | Fenway Park | MLB Network | Red Sox, 2–1 |
| 4 | October 11 | Monday | Rays 5, Red Sox 6 | Fenway Park | Fox Sports 1 | Red Sox, 3–1 |

#### Game 1

For the ALDS roster, Boston added J. D. Martinez, Martín Pérez, Chris Sale, and Danny Santana, while omitting Jonathan Araúz, Matt Barnes, Jarren Duran, and Connor Wong.
Tampa Bay won the opening game of the series, 5–0. Boston started Eduardo Rodríguez took the loss after allowing two runs on two hits and two walks in 1+2⁄3 innings. Tampa Bay's other three runs were charged to Nick Pivetta, who pitched 4+2⁄3 innings of relief. Randy Arozarena of the Rays walked against Pivetta in the seventh inning, advanced to third base on a double by Wander Franco, and then stole home against Josh Taylor, who had relieved Pivetta. The Red Sox outhit the Rays, 9–6, but went 1-for-7 with runners in scoring position.

#### Game 2

Prior to the second game of the series, Boston added Matt Barnes to their active roster, replacing Garrett Richards, who was placed on the injured list with a strained left hamstring.
Boston evened the series at 1–1 with a 14–6 win in Game 2. After the Red Sox scored twice in the top of the first inning, the Rays scored five runs off of Chris Sale in the bottom of the inning, including a grand slam by Jordan Luplow. The Boston bullpen, led by five innings from Tanner Houck, allowed just one more run by Tampa Bay—a home run by Ji-man Choi—for the rest of the game. Meanwhile, the Red Sox scored 12 more runs and had five batters with three or more hits. Kiké Hernández had five hits including a home run and three doubles. Xander Bogaerts, Alex Verdugo, J. D. Martinez, and Rafael Devers also homered. Houck got the win in relief for Boston, while Tampa Bay reliever Collin McHugh, who allowed three runs on two hits and a walk in 1+2⁄3 innings, took the loss.

#### Game 3

Boston took a 2–1 lead in the series with a 6–4 win in a 13-inning Game 3. The Rays scored twice in the top of the first inning, via a two-run homer by Austin Meadows. The Red Sox got a run back in the bottom of the inning on a Kyle Schwarber solo homer. Boston went ahead, 3–2, on four consecutive singles that scored two runs in the bottom of the third, and extended the lead to 4–2 via a fifth-inning solo home run by Kiké Hernández. In the top of the eighth, Wander Franco homered and Randy Arozarena hit an RBI double, both off of Hansel Robles, as the Rays tied the game, 4–4. After a scoreless ninth inning, the game went to extra innings. Nick Pivetta, expected to be Boston's starting pitcher in Game 4, came on in relief and held the Rays scoreless in the top of the 10th, while the Rays' David Robertson held Boston scoreless in the bottom of the inning. Both Pivetta and Robertson stayed in the game and pitched a scoreless 11th inning. Pivetta again held the Rays scoreless in the top of the 12th, while Luis Patiño held the Red Sox scoreless in the bottom of the inning. Pivetta pitched a fourth scoreless inning, the 13th, which included a ground-rule double by Kevin Kiermaier—the batted ball bounced off of the right field wall, the ground, and then off of Hunter Renfroe into the bullpen—which otherwise would have resulted in a Rays run, as Yandy Díaz was running from first base when the ball was hit. Christian Vázquez ended the game via a two-run walk-off home run off of Patiño in the bottom of the 13th.

#### Game 4

The Red Sox won Game 4, 6–5, to advance to the ALCS. Eduardo Rodríguez, who had lost Game 1 but only threw 41 pitches, started for Boston, while Collin McHugh, who had lost Game 2 in relief, started for Tampa Bay. After two scoreless innings, Boston scored five runs in the bottom of the third, including a three-run homer by Rafael Devers. The Rays got one run back in the top of the fifth. In the top of the sixth, a two-run homer by Wander Franco cut Boston's lead to 5–3. The Rays opened the eighth with three consecutive hits off of Ryan Brasier to tie the game, 5–5; Garrett Whitlock relieved Brasier and ended the rally. An outfield assist by Kevin Kiermaier cut down Alex Verdugo at third base to end a Red Sox threat in the bottom of the eighth. Whitlock then retired the Rays in order on seven pitches in the top of the ninth. After the Red Sox put runners at second and third with one out in the bottom of the ninth, a sacrifice fly by Kiké Hernández pushed across the winning run.

### American League Championship Series vs. Houston Astros

The Red Sox and Houston Astros, who had home field advantage, met in a rematch of the 2018 ALCS, which was won by Boston in five games.
ALCS Schedule :
| Game | Date | Day | Start time / Result | Location | Television | Series |
| 1 | October 15 | Friday | Red Sox 4, Astros 5 | Minute Maid Park | Fox | Astros, 1–0 |
| 2 | October 16 | Saturday | Red Sox 9, Astros 5 | Minute Maid Park | Fox / Fox Sports 1 | tied, 1–1 |
| 3 | October 18 | Monday | Astros 3, Red Sox 12 | Fenway Park | Fox Sports 1 | Red Sox, 2–1 |
| 4 | October 19 | Tuesday | Astros 9, Red Sox 2 | Fenway Park | Fox Sports 1 | tied, 2–2 |
| 5 | October 20 | Wednesday | Astros 9, Red Sox 1 | Fenway Park | Fox Sports 1 | Astros, 3–2 |
| 6 | October 22 | Friday | Red Sox 0, Astros 5 | Minute Maid Park | Fox Sports 1 | Astros, 4–2 |

#### Game 1

For the ALCS roster, manager Alex Cora made two changes to Red Sox' bullpen; Darwinzon Hernández and Hirokazu Sawamura were added, while Matt Barnes and Austin Davis were removed.
Houston took a 1–0 lead in the series via a 5–4 win in Game 1. The Red Sox loaded the bases with two outs in the top of the first, but were unable to score. The Astros scored a run in the bottom of the first; Jose Altuve, who had drawn a leadoff walk, scored on a sacrifice fly by Yordan Alvarez. In the bottom of the second, Houston loaded the bases with one out but did not score. A leadoff home run by Kiké Hernández in the top of the third tied the game. A one-out walk by Xander Bogaerts, followed by a single and an error, gave Boston a 2–1 lead, and Hunter Renfroe then doubled to make it a 3–1 game. With two out in the top of the third, Yimi García relieved Houston starter Framber Valdez. Boston starter Chris Sale left with two on and two out in the bottom of the third, relieved by Adam Ottavino. A two-run homer by Altuve off of Tanner Houck with two out in the bottom of the sixth tied the game, 3–3. Carlos Correa put Houston ahead, 4–3, with a solo home run in the bottom of the seventh off of Hansel Robles. After the Astros loaded the bases with none out in the bottom of the eighth off of Sawamura, an Altuve sacrifice fly gave Houston a 5–3 lead. Boston got a run back to start the ninth, as Hernández homered off of Houston closer Ryan Pressly. Pressly then retired the next three batters, giving Houston the win. The teams combined to use 16 total pitchers in the game, eight each.

#### Game 2

Boston tied the series at one game each with a 9–5 win in Game 2. Starting pitchers were Nathan Eovaldi for Boston, and Luis García for Houston. J. D. Martinez hit a grand slam in the top of the first to give Boston a 4–0 lead over the Astros. It was the first postseason grand slam in the first inning by a Red Sox player since J. D. Drew in 2007 ALCS Game 6. García left with none out in the top of the second due to knee discomfort. Rafael Devers hit a second grand slam in the top of the second, making the Red Sox the first team in postseason history to hit two grand slams in one game. A fourth-inning homer by Kiké Hernández, his third of the series, made it 9–0. The Astros rallied with two outs in the bottom of the fourth for three runs, trimming Boston's lead to 9–3. Eovaldi left after 5+1⁄3 innings, relieved by Adam Ottavino. Yuli Gurriel and Jason Castro each hit solo home runs off of Darwinzon Hernández in the bottom of the ninth, making it 9–5, the final score.

#### Game 3

Boston won Game 3, 12–3, to take a 2–1 lead in the series. Eduardo Rodríguez started for Boston and José Urquidy started for Houston. The Red Sox sent 11 men to the plate in the bottom of the second, scoring six runs. Four of the runs came on a grand slam by Kyle Schwarber, the third by a Red Sox batter in two games. Urquidy left with two outs in the second, having allowed six runs (five earned) on five hits and two walks while striking out one batter. Boston added three runs in the bottom of the third, including a two-run homer by Christian Arroyo, extending the Red Sox' lead to 9–0. Astros right fielder Kyle Tucker hit a three-run homer with two out in the top of the fourth, making it a 9–3 game. Boston made it 11–3 in the bottom of the sixth via a two-run homer by J. D. Martinez. Hansel Robles relieved Rodríguez in the top of the seventh, Rodríguez allowed three runs on five hits and no walks while striking out seven in what would turn out to be his final start in a Red Sox uniform. Rafael Devers hit a solo home run in the bottom of the eighth, extending the lead to 12–3, the final score.

#### Game 4

Houston won Game 4, 9–2, powered by a seven-run ninth inning to even the series, 2–2. Nick Pivetta started for Boston and Zack Greinke started for Houston. The Astros took an early 1–0 lead via a solo home run by Alex Bregman with two outs in the top of the first. In the bottom of the first, Rafael Devers walked with two outs, then Xander Bogaerts homered to give the Red Sox a 2–1 lead. Greinke left with one out in the bottom of the second, having allowed two runs on one hit and three walks; he did not strike out a batter. Christian Arroyo hit a one-out triple in the bottom of the fourth, but the Red Sox were unable to score him. Bogaerts hit a one-out double in the bottom of the fifth and was also left stranded. Pivetta left after the fifth inning, having allowed one run on two hits and two walks; he struck out three. Jose Altuve tied the game, 2–2, with a home run off of Garrett Whitlock to lead off the eighth inning. Nate Eovaldi came in to pitch the top of the ninth, and Carlos Correa led off with a double over Hunter Renfroe in right field. With two outs, Jason Castro singled to drive in Correa and give the Astros a 3–2 lead. Houston was able to load the bases, and Boston brought in Martín Pérez. Michael Brantley hit his first pitch for a double that scored three runs, giving Houston a 6–2 lead. A single by Yordan Alvarez plated another run, making it 7–2. Correa, batting for the second time in the inning, hit a ball fielded by Pérez that was thrown away for an error, allowing another run to score, and a single by Kyle Tucker drove in the Astros' seventh and final run of the inning. Houston closer Ryan Pressly came in to pitch the bottom of the ninth; he allowed two singles, but prevented Boston from scoring as Houston evened the series.

#### Game 5

Houston won Game 5 by a 9–1 score, putting them a win away from the AL pennant, with the remaining game(s) of the series to be played in Houston. Chris Sale started for the Red Sox and Framber Valdez started for the Astros. Houston took a 1–0 lead on a solo home run by Yordan Alvarez in the top of the second inning. Valdez did not allow a Boston baserunner until the fifth inning. The Astros scored five runs in the top of the sixth, chasing Sale with one out. Houston's runs came on four hits, a walk, and an error, giving the Astros a 6–0 lead. The teams traded runs in the seventh, making it 7–1. Boston's only run of the game was a solo homer by Rafael Devers. Houston added two more runs in the top of the ninth, for the 9–1 final. Valdez went eight innings and got the win, limiting Boston to one run on three hits and a walk while striking out five batters. Sale took the loss, having pitched 5+1⁄3 inning while allowing four runs (two earned) on three hits and two walks while striking out seven.

#### Game 6

Luis García started for Houston and Nathan Eovaldi for Boston, a rematch of Game 2. The Astros took a 1–0 lead in the bottom of the first; with two outs, Alex Bregman singled then was driven in on a double by Yordan Alvarez that hit off the glove of Red Sox center fielder Kiké Hernández. In the bottom of the fourth, Houston had runners on second and third with no outs, but Eovaldi struck out the next two batters, intentionally walked Yuli Gurriel, and then struck out Chas McCormick to end the threat. Eovaldi left with one out in the bottom of the fifth, having allowed one run on five hits while striking out four; he was relieved by Josh Taylor. García held the Red Sox hitless through five innings; he left in the top of the sixth after allowing a two-out triple to Hernández. García was relieved by Phil Maton, who ended the threat by getting Rafael Devers to pop out. Alvarez opened the bottom of the sixth with a triple off of Taylor near the right-field line. After Carlos Correa was hit by a pitch from Tanner Houck, Kyle Tucker grounded into a double play, scoring Alvarez and giving Houston a 2–0 lead. In the top of the seventh, Boston had runners at first and third with one out; Kendall Graveman struck out Travis Shaw and catcher Martín Maldonado threw out Alex Verdugo, who had been running on the pitch, at second base to end the inning. Alvarez collected his fourth hit of the game in the bottom of the eighth, singling to give the Astros runners at first and second with one out. After Correa grounded out, Tucker homered off of Adam Ottavino, extending Houston's lead to 5–0. Astros closer Ryan Pressly entered to pitch the top of the ninth. He retired the side in order, as Houston advanced to the World Series.

### Postseason rosters

Playoff rosters :
American League Wild Card Game
Pitchers: 0 Adam Ottavino 17 Nathan Eovaldi 32 Matt Barnes 37 Nick Pivetta 38 Josh Taylor 43 Garrett Richards 56 Hansel Robles 57 Eduardo Rodríguez 65 Austin Davis 70 Ryan Brasier 72 Garrett Whitlock 89 Tanner Houck
Catchers: 7 Christian Vázquez 25 Kevin Plawecki 74 Connor Wong
Infielders: 2 Xander Bogaerts 3 Jonathan Araúz 11 Rafael Devers 23 Travis Shaw 29 Bobby Dalbec 39 Christian Arroyo
Oufielders: 5 Kiké Hernández 10 Hunter Renfroe 18 Kyle Schwarber 40 Jarren Duran 99 Alex Verdugo :
American League Division Series
Pitchers: 0 Adam Ottavino 17 Nathan Eovaldi 32 Matt Barnes (Games 2–4) 37 Nick Pivetta 38 Josh Taylor 41 Chris Sale 43 Garrett Richards (Game 1) 54 Martín Pérez 56 Hansel Robles 57 Eduardo Rodríguez 65 Austin Davis 70 Ryan Brasier 72 Garrett Whitlock 89 Tanner Houck
Catchers: 7 Christian Vázquez 25 Kevin Plawecki
Infielders: 2 Xander Bogaerts 11 Rafael Devers 23 Travis Shaw 29 Bobby Dalbec 39 Christian Arroyo
Outfielders: 5 Kiké Hernández 10 Hunter Renfroe 18 Kyle Schwarber 22 Danny Santana 99 Alex Verdugo
Designated hitters: 28 J. D. Martinez :
American League Championship Series
Pitchers: 0 Adam Ottavino 17 Nathan Eovaldi 19 Hirokazu Sawamura 37 Nick Pivetta 38 Josh Taylor 41 Chris Sale 54 Martín Pérez 56 Hansel Robles 57 Eduardo Rodríguez 63 Darwinzon Hernández 70 Ryan Brasier 72 Garrett Whitlock 89 Tanner Houck
Catchers: 7 Christian Vázquez 25 Kevin Plawecki
Infielders: 2 Xander Bogaerts 11 Rafael Devers 23 Travis Shaw 29 Bobby Dalbec 39 Christian Arroyo
Outfielders: 5 Kiké Hernández 10 Hunter Renfroe 18 Kyle Schwarber 22 Danny Santana 99 Alex Verdugo
Designated hitters: 28 J. D. Martinez :

## Season standings
### American League East

vteAL East :
| Team | W | L | Pct. | GB | Home | Road |
| Tampa Bay Rays | 100 | 62 | .617 | — | 52‍–‍29 | 48‍–‍33 |
| Boston Red Sox | 92 | 70 | .568 | 8 | 49‍–‍32 | 43‍–‍38 |
| New York Yankees | 92 | 70 | .568 | 8 | 46‍–‍35 | 46‍–‍35 |
| Toronto Blue Jays | 91 | 71 | .562 | 9 | 47‍–‍33 | 44‍–‍38 |
| Baltimore Orioles | 52 | 110 | .321 | 48 | 27‍–‍54 | 25‍–‍56 |

### Record against opponents
#### American League

2021 American League recordvte
Source: MLB Standings Grid – 2021 :
| Team | BAL | BOS | CWS | CLE | DET | HOU | KC | LAA | MIN | NYY | OAK | SEA | TB | TEX | TOR | NL |
| Baltimore | — | 6–13 | 0–7 | 2–5 | 2–5 | 3–3 | 4–3 | 2–4 | 2–4 | 8–11 | 3–3 | 3–4 | 1–18 | 4–3 | 5–14 | 7–13 |
| Boston | 13–6 | — | 3–4 | 4–2 | 3–3 | 2–5 | 5–2 | 3–3 | 5–2 | 10–9 | 3–3 | 4–3 | 8–11 | 3–4 | 10–9 | 16–4 |
| Chicago | 7–0 | 4–3 | — | 10–9 | 12–7 | 2–5 | 9–10 | 2–5 | 13–6 | 1–5 | 4–3 | 3–3 | 3–3 | 5–1 | 4–3 | 14–6 |
| Cleveland | 5–2 | 2–4 | 9–10 | — | 12–7 | 1–6 | 14–5 | 5–1 | 8–11 | 3–4 | 2–4 | 3–4 | 1–6 | 4–2 | 2–5 | 9–11 |
| Detroit | 5–2 | 3–3 | 7–12 | 7–12 | — | 5–2 | 8–11 | 1–6 | 8–11 | 3–3 | 1–6 | 5–1 | 4–3 | 6–1 | 3–3 | 11–9 |
| Houston | 3–3 | 5–2 | 5–2 | 6–1 | 2–5 | — | 3–4 | 13–6 | 3–4 | 2–4 | 11–8 | 11–8 | 4–2 | 14–5 | 4–2 | 9–11 |
| Kansas City | 3–4 | 2–5 | 10–9 | 5–14 | 11–8 | 4–3 | — | 2–4 | 10–9 | 2–4 | 2–5 | 4–3 | 2–4 | 2–4 | 3–4 | 12–8 |
| Los Angeles | 4–2 | 3–3 | 5–2 | 1–5 | 6–1 | 6–13 | 4–2 | — | 5–2 | 4–3 | 4–15 | 8–11 | 1–6 | 11–8 | 4–3 | 11–9 |
| Minnesota | 4–2 | 2–5 | 6–13 | 11–8 | 11–8 | 4–3 | 9–10 | 2–5 | — | 1–6 | 1–5 | 2–4 | 3–3 | 4–3 | 3–4 | 10–10 |
| New York | 11–8 | 9–10 | 5–1 | 4–3 | 3–3 | 4–2 | 4–2 | 3–4 | 6–1 | — | 4–3 | 5–2 | 8–11 | 6–1 | 8–11 | 12–8 |
| Oakland | 3–3 | 3–3 | 3–4 | 4–2 | 6–1 | 8–11 | 5–2 | 15–4 | 5–1 | 3–4 | — | 4–15 | 4–3 | 10–9 | 2–5 | 11–9 |
| Seattle | 4–3 | 3–4 | 3–3 | 4–3 | 1–5 | 8–11 | 3–4 | 11–8 | 4–2 | 2–5 | 15–4 | — | 6–1 | 13–6 | 4–2 | 9–11 |
| Tampa Bay | 18–1 | 11–8 | 3–3 | 6–1 | 3–4 | 2–4 | 4–2 | 6–1 | 3–3 | 11–8 | 3–4 | 1–6 | — | 3–4 | 11–8 | 15–5 |
| Texas | 3–4 | 4–3 | 1–5 | 2–4 | 1–6 | 5–14 | 4–2 | 8–11 | 3–4 | 1–6 | 9–10 | 6–13 | 4–3 | — | 2–4 | 7–13 |
| Toronto | 14–5 | 9–10 | 3–4 | 5–2 | 3–3 | 2–4 | 4–3 | 3–4 | 4–3 | 11–8 | 5–2 | 2–4 | 8–11 | 4–2 | — | 14–6 |
Updated with the results of all games through October 3, 2021.

#### National League

Red Sox vs. National League East :
| Team | ATL | MIA | NYM | PHI | WSH |
| Boston | 3–1 | 3–0 | 4–0 | 3–3 | 3–0 |
Reflects all interleague games of the regular season.

## Game log

| Red Sox Win | Red Sox Loss | Game Postponed | Clinched Playoff Spot |
2021 Boston Red Sox Season Game Log: 92–70 (Home: 49–32; Away: 43–38) :
April: 17–10 (Home: 8–8; Away: 9–2)
#DateOpponentScoreWinLossSaveStadiumAttendanceRecordBox/ Streak
—April 1OriolesPostponed (rain). Makeup date April 2.
1April 2Orioles0–3Means (1–0)Eovaldi (0–1)Valdez (1)Fenway Park4,4520–1L1
2April 3Orioles2–4Plutko (1–0)Houck (0–1)Valdez (2)Fenway Park4,5710–2L2
3April 4Orioles3–11Zimmermann (1–0)Richards (0–1)—Fenway Park4,4580–3L3
4April 5Rays11–2Pivetta (1–0)Wacha (0–1)—Fenway Park4,5771–3W1
5April 6Rays6–5 (12)Valdéz (1–0)Thompson (0–1)—Fenway Park4,6822–3W2
6April 7Rays9–2Eovaldi (1–1)Yarbrough (0–1)—Fenway Park4,7513–3W3
7April 8@ Orioles7–3Rodríguez (1–0)Harvey (0–1)—Camden Yards10,1504–3W4
8April 10@ Orioles6–4 (10)Barnes (1–0)Tate (0–1)Andriese (1)Camden Yards9,3075–3W5
9April 11@ Orioles14–9Pivetta (2–0)López (0–2)—Camden Yards8,1716–3W6
–April 12@ TwinsPostponed (protests due to killing of Daunte Wright). Makeup date April 14.
10April 13@ Twins4–2Ottavino (1–0)Dobnak (0–2)Barnes (1)Target Field6,7247–3W7
11April 14 (1)@ Twins3–2 (7)Eovaldi (2–1)Maeda (1–1)Barnes (2)Target Field7,0748–3W8
12April 14 (2)@ Twins7–1 (7)Rodríguez (2–0)Berríos (2–1)—Target Field9–3W9
13April 15@ Twins3–4Colomé (1–1)Ottavino (1–1)—Target Field7,9259–4L1
—April 16White SoxPostponed (snow). Makeup date April 18.
14April 17White Sox7–4Ottavino (2–1)Heuer (1–1)—Fenway Park4,66810–4W1
15April 18 (1)White Sox2–3 (7)Keuchel (1–0)Houck (0–2)Hendriks (2)Fenway Park4,67910–5L1
16April 18 (2)White Sox1–5 (7)Foster (1–1)Pérez (0–1)—Fenway Park4,60110–6L2
17April 19White Sox11–4Eovaldi (3–1)Giolito (1–1)—Fenway Park4,73811–6W1
18April 20Blue Jays4–2Rodríguez (3–0)Ryu (1–2)Barnes (3)Fenway Park4,72812–6W2
19April 21Blue Jays3–6Borucki (2–1)Richards (0–2)Castro (1)Fenway Park4,66112–7L1
20April 22Mariners3–7 (10)Montero (2–0)Hernández (0–1)—Fenway Park4,61712–8L2
21April 23Mariners6–5Sawamura (1–0)Kikuchi (0–1)—Fenway Park4,64613–8W1
22April 24Mariners2–8Flexen (2–1)Eovaldi (3–2)—Fenway Park4,62113–9L1
23April 25Mariners5–3Rodríguez (4–0)Margevicius (0–2)Barnes (4)Fenway Park4,51014–9W1
24April 27@ Mets2–1Richards (1–2)Peterson (1–3)Barnes (5)Citi Field7,91715–9W2
25April 28@ Mets1–0Pivetta (3–0)deGrom (2–2)Barnes (6)Citi Field8,05116–9W3
26April 29@ Rangers1–4Gibson (3–0)Pérez (0–2)Kennedy (5)Globe Life Field23,64016–10L1
27April 30@ Rangers6–1Eovaldi (4–2)Arihara (2–3)—Globe Life Field28,26717–10W1 :
May: 15–11 (Home: 8–5; Away: 7–6)
#DateOpponentScoreWinLossSaveStadiumAttendanceRecordBox/ Streak
28May 1@ Rangers6–8Sborz (2–1)Andriese (0–1)Kennedy (6)Globe Life Field35,12917–11L1
29May 2@ Rangers3–5Sborz (3–1)Ottavino (2–2)Kennedy (7)Globe Life Field29,19017–12L2
30May 4Tigers11–7Pivetta (4–0)Fulmer (1–2)Barnes (7)Fenway Park4,67718–12W1
31May 5Tigers5–6 (10)Soto (2–1)Whitlock (0–1)Fulmer (1)Fenway Park4,66118–13L1
32May 6Tigers12–9Andriese (1–1)Lange (0–1)Ottavino (1)Fenway Park4,73419–13W1
33May 7@ Orioles6–2Rodríguez (5–0)Harvey (3–2)—Camden Yards7,72420–13W2
34May 8@ Orioles11–6Richards (2–2)Lowther (0–1)—Camden Yards10,59821–13W3
35May 9@ Orioles4–3Pivetta (5–0)Kremer (0–3)Barnes (8)Camden Yards10,27422–13W4
36May 10@ Orioles1–4Scott (2–2)Andriese (1–2)Valdez (8)Camden Yards6,82622–14L1
37May 11Athletics2–3Bassitt (3–2)Hernández (0–2)Diekman (4)Fenway Park9,26422–15L2
38May 12Athletics1–4Kaprielian (1–0)Rodríguez (5–1)Diekman (5)Fenway Park9,27222–16L3
39May 13Athletics8–1Richards (3–2)Manaea (3–2)Whitlock (1)Fenway Park9,30123–16W1
40May 14Angels4–3Andriese (2–2)Watson (1–1)Barnes (9)Fenway Park9,28424–16W2
41May 15Angels9–0Pérez (1–2)Bundy (0–5)—Fenway Park9,37425–16W3
42May 16Angels5–6Iglesias (2–2)Barnes (1–1)Mayers (2)Fenway Park9,31625–17L1
43May 18@ Blue Jays0–8Ryu (4–2)Rodríguez (5–2)—TD Ballpark1,56625–18L2
44May 19@ Blue Jays7–3Richards (4–2)Stripling (0–3)—TD Ballpark1,58126–18W1
45May 20@ Blue Jays8–7Valdéz (2–0)Dolis (1–1)Barnes (10)TD Ballpark1,56227–18W2
46May 21@ Phillies11–3Pérez (2–2)Nola (3–4)—Citizens Bank Park15,27928–18W3
47May 22@ Phillies4–3Eovaldi (5–2)Howard (0–1)Barnes (11)Citizens Bank Park15,42429–18W4
48May 23@ Phillies2–6Wheeler (4–2)Rodríguez (5–3)—Citizens Bank Park15,36029–19L1
49May 25Braves1–3Morton (3–2)Richards (4–3)Smith (8)Fenway Park9,35729–20L2
50May 26Braves9–5Pivetta (6–0)Smyly (2–3)—Fenway Park9,19730–20W1
51May 28Marlins5–2 (6)Pérez (3–2)Poteet (2–1)Ottavino (2)Fenway Park9,00531–20W2
52May 29Marlins3–1Eovaldi (6–2)Rogers (6–3)Barnes (12)Fenway Park25,08932–20W3
—May 30MarlinsPostponed (rain). Makeup date June 7.
53May 31@ Astros2–11Urquidy (4–2)Rodríguez (5–4)—Minute Maid Park28,54332–21L1 :
June: 18–10 (Home: 10–4; Away: 8–6)
#DateOpponentScoreWinLossSaveStadiumAttendanceRecordBox/ Streak
54June 1@ Astros1–5García (4–3)Richards (4–4)—Minute Maid Park23,44932–22L2
55June 2@ Astros1–2Valdez (1–0)Pivetta (6–1)Pressly (8)Minute Maid Park22,66432–23L3
56June 3@ Astros5–1Pérez (4–2)Odorizzi (0–3)—Minute Maid Park24,85333–23W1
57June 4@ Yankees5–2Eovaldi (7–2)King (0–3)Barnes (13)Yankee Stadium18,04034–23W2
58June 5@ Yankees7–3Whitlock (1–1)Green (0–4)Barnes (14)Yankee Stadium20,01935–23W3
59June 6@ Yankees6–5 (10)Barnes (2–1)Cessa (1–1)Valdéz (1)Yankee Stadium19,10336–23W4
60June 7Marlins5–3Sawamura (2–0)Thompson (0–1)Ottavino (3)Fenway Park25,37437–23W5
61June 8Astros1–7Valdez (2–0)Pérez (4–3)—Fenway Park23,60437–24L1
62June 9Astros3–8Odorizzi (1–3)Eovaldi (7–3)Javier (1)Fenway Park21,00737–25L2
63June 10Astros12–8Hernández (1–2)Taylor (0–1)—Fenway Park23,37838–25W1
64June 11Blue Jays6–5Whitlock (2–1)Dolis (1–2)—Fenway Park25,25739–25W2
65June 12Blue Jays2–7Matz (7–3)Pivetta (6–2)—Fenway Park24,02439–26L1
66June 13Blue Jays4–18Ray (4–2)Pérez (4–4)—Fenway Park22,59539–27L2
67June 14Blue Jays2–1Barnes (3–1)Dolis (1–3)—Fenway Park20,07040–27W1
68June 15@ Braves10–8Sawamura (3–0)Martin (0–3)Barnes (15)Truist Park36,63841–27W2
69June 16@ Braves10–8Ríos (1–0)Greene (0–1)Ottavino (4)Truist Park39,84742–27W3
70June 18@ Royals3–5Bubic (2–2)Pivetta (6–3)Holland (4)Kauffman Stadium29,87042–28L1
71June 19@ Royals7–1Pérez (5–4)Keller (6–7)—Kauffman Stadium24,56843–28W1
72June 20@ Royals3–7Minor (6–4)Eovaldi (7–4)—Kauffman Stadium20,72643–29L1
73June 22@ Rays9–5 (11)Hernández (2–2)Fairbanks (1–3)—Tropicana Field12,99444–29W1
74June 23@ Rays2–8Hill (6–2)Richards (4–5)—Tropicana Field9,08844–30L1
75June 24@ Rays0–1Feyereisen (4–3)Barnes (3–2)—Tropicana Field10,96144–31L2
76June 25Yankees5–3Whitlock (3–1)Germán (4–5)Barnes (16)Fenway Park36,86945–31W1
77June 26Yankees4–2Eovaldi (8–4)Montgomery (3–2)Ottavino (5)Fenway Park36,85746–31W2
78June 27Yankees9–2Rodríguez (6–4)Cole (8–4)—Fenway Park34,50447–31W3
79June 28Royals6–5Sawamura (4–0)Staumont (0–2)Barnes (17)Fenway Park22,76648–31W4
80June 29Royals7–6Ríos (2–0)Brentz (2–1)Barnes (18)Fenway Park25,18049–31W5
81June 30Royals6–2Pérez (6–4)Minor (6–6)—Fenway Park24,61650–31W6 :
July: 13–12 (Home: 7–5; Away: 6–7)
#DateOpponentScoreWinLossSaveStadiumAttendanceRecordBox/ Streak
82July 1Royals15–1Eovaldi (9–4)Bubic (2–4)—Fenway Park27,91351–31W7
83July 2@ Athletics3–2 (10)Barnes (4–2)Trivino (3–3)Ottavino (6)Oakland Coliseum32,30452–31W8
84July 3@ Athletics6–7 (12)Wendelken (1–0)Andriese (2–3)—Oakland Coliseum16,29752–32L1
85July 4@ Athletics1–0Pivetta (7–3)Kaprielian (4–3)Barnes (19)Oakland Coliseum13,07053–32W1
86July 5@ Angels5–4Pérez (7–4)Suárez (3–2)Ottavino (7)Angel Stadium38,20154–32W2
87July 6@ Angels3–5Ohtani (4–1)Eovaldi (9–5)Iglesias (17)Angel Stadium28,68954–33L1
88July 7@ Angels4–5Heaney (5–6)Rodríguez (6–5)Iglesias (18)Angel Stadium20,00154–34L2
89July 9Phillies11–5Richards (5–5)Velasquez (3–4)—Fenway Park32,64155–34W1
90July 10Phillies2–11Falter (1–0)Pérez (7–5)—Fenway Park33,20255–35L1
91July 11Phillies4–5Sánchez (1–0)Pivetta (7–4)Suárez (2)Fenway Park32,58655–36L2
—July 15@ YankeesPostponed (COVID-19). Makeup date August 17.
92July 16@ Yankees4–0Rodríguez (7–5)Montgomery (3–5)Houck (1)Yankee Stadium40,13056–36W1
93July 17@ Yankees1–3 (6)Cole (10–4)Sawamura (4–1)—Yankee Stadium37,09556–37L1
94July 18@ Yankees1–9Taillon (5–4)Pérez (7–6)—Yankee Stadium40,30956–38L2
95July 19@ Blue Jays13–4Pivetta (8–4)Stripling (3–6)—Sahlen Field12,81157–38W1
—July 20@ Blue JaysPostponed (Rain). Makeup date August 7.
96July 21@ Blue Jays7–4Richards (6–5)Ray (8–5)Barnes (20)Sahlen Field14,60758–38W2
97July 22Yankees5–4 (10)Barnes (5–2)Kriske (1–1)—Fenway Park34,76159–38W3
98July 23Yankees6–2Ríos (3–0)Cole (10–5)—Fenway Park34,92260–38W4
99July 24Yankees3–4Taillon (6–4)Ottavino (2–3)Chapman (18)Fenway Park35,13660–39L1
100July 25Yankees5–4Workman (1–2)Loáisiga (7–4)Barnes (21)Fenway Park32,00961–39W1
101July 26Blue Jays5–4Ottavino (3–3)Richards (4–1)Barnes (22)Fenway Park27,14262–39W2
—July 27Blue JaysPostponed (Rain). Makeup date July 28.
102July 28 (1)Blue Jays1–4 (7)Ray (9–5)Richards (6–6)Romano (8)Fenway Park27,41062–40L1
103July 28 (2)Blue Jays4–1 (7)Whitlock (4–1)Matz (8–6)Barnes (23)Fenway Park27,78363–40W1
104July 29Blue Jays1–13Ryu (10–5)Rodríguez (7–6)—Fenway Park33,19163–41L1
105July 30@ Rays3–7Fleming (8–5)Pérez (7–7)—Tropicana Field11,10963–42L2
106July 31@ Rays5–9Kittredge (7–1)Eovaldi (9–6)—Tropicana Field20,52163–43L3 :
August: 12–16 (Home: 8–4; Away: 4–12)
#DateOpponentScoreWinLossSaveStadiumAttendanceRecordBox/ Streak
107August 1@ Rays2–3McClanahan (5–4)Pivetta (8–5)Wisler (1)Tropicana Field17,81663–44L4
108August 3@ Tigers2–4Funkhouser (5–1)Richards (6–7)Soto (12)Comerica Park15,72463–45L5
109August 4@ Tigers4–1Rodríguez (8–6)Mize (6–6)Barnes (24)Comerica Park16,63364–45W1
110August 5@ Tigers1–8Skubal (7–10)Pérez (7–8)—Comerica Park19,14464–46L1
111August 6@ Blue Jays4–12Manoah (4–1)Eovaldi (9–7)—Rogers Centre14,71964–47L2
112August 7 (1)@ Blue Jays0–1 (7)Romano (5–1)Barnes (5–3)—Rogers Centre14,76864–48L3
113August 7 (2)@ Blue Jays2–1 (8)Barnes (6–3)Cimber (2–3)Ottavino (8)Rogers Centre12,65965–48W1
114August 8@ Blue Jays8–9Dolis (2–3)Barnes (6–4)Romano (10)Rogers Centre14,76665–49L1
115August 10Rays4–8Kittredge (8–1)Barnes (6–5)—Fenway Park25,35665–50L2
116August 11Rays20–8Eovaldi (10–7)Fleming (9–6)—Fenway Park30,28666–50W1
117August 12Rays1–8McHugh (4–1)Houck (0–3)—Fenway Park26,80366–51L1
118August 13Orioles8–1Pivetta (9–5)Watkins (2–4)Richards (1)Fenway Park28,02267–51W1
119August 14Orioles16–2Sale (1–0)López (3–13)—Fenway Park33,11868–51W2
120August 15Orioles6–2Rodríguez (9–6)Akin (0–7)—Fenway Park28,93569–51W3
121August 17 (1)@ Yankees3–5 (7)Abreu (2–0)Whitlock (4–2)Loaisiga (5)Yankee Stadium39,07869–52L1
122August 17 (2)@ Yankees0–2 (7)Peralta (4–2)Eovaldi (10–8)Green (5)Yankee Stadium35,23769–53L2
123August 18@ Yankees2–5Heaney (8–8)Pivetta (9–6)Luetge (1)Yankee Stadium39,16669–54L3
124August 20Rangers6–0Sale (2–0)Dunning (5–8)—Fenway Park30,01270–54W1
125August 21Rangers1–10Lyles (6–10)Rodríguez (9–7)—Fenway Park32,49570–55L1
—August 22RangersPostponed (rain, makeup August 23)
126August 23Rangers8–4 (11)Whitlock (5–2)Santana (2–3)—Fenway Park27,65271–55W1
127August 24Twins11–9Taylor (1–0)Jax (3–2)Robles (11)Fenway Park27,98672–55W2
128August 25Twins6–9 (10)Colomé (4–4)Robles (3–5)—Fenway Park28,92372–56L1
129August 26Twins12–2Sale (3–0)Gant (4–8)—Fenway Park33,74673–56W1
130August 27@ Indians4–3Rodríguez (10–7)Karinchak (7–4)Ottavino (9)Progressive Field20,88174–56W2
131August 28@ Indians5–3 (10)Whitlock (6–2)Wittgren (2–7)Ottavino (10)Progressive Field26,22175–56W3
132August 29@ Indians5–7Shaw (6–6)Davis (0–2)Clase (19)Progressive Field22,88375–57L1
133August 30@ Rays1–6Patiño (4–3)Pivetta (9–7)—Tropicana Field6,75375–58L2
134August 31@ Rays5–8Yarbrough (8–4)Peacock (0–1)Kittredge (5)Tropicana Field6,86875–59L3 :
September: 14–11 (Home: 8–6; Away: 6–5)
#DateOpponentScoreWinLossSaveStadiumAttendanceRecordBox/ Streak
135September 1@ Rays3–2Whitlock (7–2)Fairbanks (3–5)Ottavino (11)Tropicana Field7,80876–59W1
136September 2@ Rays4–0Rodríguez (11–7)McClanahan (9–5)Richards (2)Tropicana Field7,92377–59W2
137September 3Indians8–5Ottavino (4–3)Quantrill (4–3)Whitlock (2)Fenway Park31,12778–59W3
138September 4Indians4–3Ottavino (5–3)Shaw (6–7)—Fenway Park33,08179–59W4
139September 5Indians5–11Plesac (10–4)Crawford (0–1)Clase (21)Fenway Park27,57879–60L1
140September 6Rays10–11 (10)McHugh (6–1)Whitlock (7–3)—Fenway Park26,51279–61L2
141September 7Rays7–12Rasmussen (2–1)Rodriguez (11–8)—Fenway Park25,06579–62L3
142September 8Rays2–1Richards (7–7)Chargois (5–1)Robles (12)Fenway Park26,64980–62W1
143September 10@ White Sox3–4Rodón (12–5)Houck (0–4)Hendriks (34)Guaranteed Rate Field34,36580–63L1
144September 11@ White Sox9–8 (10)Whitlock (8–3)Wright (0–1)Taylor (1)Guaranteed Rate Field37,85481–63W1
145September 12@ White Sox1–2Kimbrel (4–4)Whitlock (8–4)—Guaranteed Rate Field36,17881–64L1
146September 13@ Mariners4–5Castillo (4–5)Brasier (0–1)Steckenrider (9)T-Mobile Park18,21981–65L2
147September 14@ Mariners8–4Ottavino (6–3)Smith (2–4)—T-Mobile Park19,88782–65W1
148September 15@ Mariners9–4 (10)Ottavino (7–3)Swanson (0–3)—T-Mobile Park17,86083–65W2
149September 17Orioles7–1Sale (4–0)Akin (2–10)—Fenway Park29,81184–65W3
150September 18Orioles9–3Houck (1–4)Baumann (1–1)—Fenway Park30,02785–65W4
151September 19Orioles8–6Sawamura (5–1)Greene (1–1)Richards (3)Fenway Park27,01086–65W5
152September 21Mets6–3Brasier (1–1)Stroman (9–13)—Fenway Park32,14687–65W6
153September 22Mets12–5Sale (5–0)Walker (7–11)—Fenway Park30,25488–65W7
154September 24Yankees3–8Cole (16–8)Eovaldi (10–9)—Fenway Park36,02688–66L1
155September 25Yankees3–5Severino (1–0)Houck (1–5)Chapman (29)Fenway Park36,10388–67L2
156September 26Yankees3–6Green (10–7)Richards (7–8)Chapman (30)Fenway Park36,31288–68L3
157September 28@ Orioles2–4Diplán (2–0)Sale (5–1)Sulser (8)Camden Yards8,09888–69L4
158September 29@ Orioles6–0Eovaldi (11–9)Lowther (1–3)—Camden Yards8,73289–69W1
159September 30@ Orioles2–6Wells (2–3)Pivetta (9–8)—Camden Yards13,01289–70L1 :
October: 3–0 (Home: 0–0; Away: 3–0)
#DateOpponentScoreWinLossSaveStadiumAttendanceRecordBox/ Streak
160October 1@ Nationals4–2Rodríguez (12–8)Rogers (2–2)Robles (13)Nationals Park32,52190–70W1
161October 2@ Nationals5–3Davis (1–2)Rainey (1–3)Robles (14)Nationals Park41,46591–70W2
162October 3@ Nationals7–5Rodríguez (13–8)Finnegan (5–9)Pivetta (1)Nationals Park33,98692–70W3 :

## Player stats
### Batting

Note: G = Games played; AB = At bats; R = Runs; H = Hits; 2B = Doubles; 3B = Triples; HR = Home runs; RBI = Runs batted in; SB = Stolen bases; BB = Walks; AVG = Batting average; SLG = Slugging average
| Player | G | AB | R | H | 2B | 3B | HR | RBI | SB | BB | AVG | SLG |
| Rafael Devers | 156 | 591 | 101 | 165 | 37 | 1 | 38 | 113 | 5 | 62 | .279 | .538 |
| J. D. Martinez | 148 | 570 | 92 | 163 | 42 | 3 | 28 | 99 | 0 | 55 | .286 | .518 |
| Alex Verdugo | 146 | 544 | 88 | 157 | 32 | 2 | 13 | 63 | 6 | 51 | .289 | .426 |
| Xander Bogaerts | 144 | 529 | 90 | 156 | 34 | 1 | 23 | 79 | 5 | 62 | .295 | .493 |
| Hunter Renfroe | 144 | 521 | 89 | 135 | 33 | 0 | 31 | 96 | 1 | 44 | .259 | .501 |
| Enrique Hernández | 134 | 508 | 84 | 127 | 35 | 3 | 20 | 60 | 1 | 61 | .250 | .449 |
| Christian Vázquez | 158 | 458 | 51 | 118 | 23 | 1 | 6 | 49 | 8 | 33 | .258 | .352 |
| Bobby Dalbec | 133 | 417 | 50 | 100 | 21 | 5 | 25 | 78 | 2 | 28 | .240 | .494 |
| Marwin González | 77 | 242 | 25 | 49 | 14 | 0 | 2 | 20 | 3 | 19 | .202 | .285 |
| Christian Arroyo | 57 | 164 | 22 | 43 | 12 | 0 | 6 | 25 | 1 | 8 | .262 | .445 |
| Kevin Plawecki | 64 | 157 | 15 | 45 | 7 | 0 | 3 | 15 | 0 | 12 | .287 | .389 |
| Kyle Schwarber | 41 | 134 | 34 | 39 | 10 | 0 | 7 | 18 | 0 | 33 | .291 | .522 |
| Franchy Cordero | 48 | 127 | 12 | 24 | 6 | 0 | 1 | 9 | 1 | 8 | .189 | .260 |
| Danny Santana | 38 | 116 | 15 | 21 | 2 | 1 | 5 | 14 | 4 | 10 | .181 | .345 |
| Jarren Duran | 33 | 107 | 17 | 23 | 3 | 2 | 2 | 10 | 2 | 4 | .215 | .336 |
| Michael Chavis | 31 | 79 | 12 | 15 | 4 | 1 | 2 | 6 | 1 | 1 | .190 | .342 |
| Jonathan Araúz | 28 | 65 | 9 | 12 | 3 | 0 | 3 | 8 | 0 | 8 | .185 | .369 |
| José Iglesias | 23 | 59 | 8 | 21 | 4 | 1 | 1 | 7 | 0 | 3 | .356 | .508 |
| Travis Shaw | 28 | 42 | 6 | 10 | 3 | 0 | 3 | 11 | 0 | 5 | .238 | .524 |
| Jack López | 7 | 13 | 2 | 2 | 2 | 0 | 0 | 0 | 0 | 1 | .154 | .308 |
| Connor Wong | 6 | 13 | 3 | 4 | 1 | 1 | 0 | 1 | 0 | 1 | .308 | .538 |
| Yairo Muñoz | 5 | 11 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | .091 | .091 |
| Taylor Motter | 3 | 6 | 3 | 2 | 1 | 1 | 0 | 1 | 0 | 1 | .333 | .833 |
| Pitcher Totals | 162 | 22 | 1 | 2 | 1 | 0 | 0 | 1 | 0 | 2 | .091 | .136 |
| Team Totals | 162 | 5495 | 829 | 1434 | 330 | 23 | 219 | 783 | 40 | 512 | .261 | .449 |
Source:

### Pitching

Note: W = Wins; L = Losses; ERA = Earned run average; G = Games pitched; GS = Games started; SV = Saves; IP = Innings pitched; H = Hits allowed; R = Runs allowed; ER = Earned runs allowed; BB = Walks allowed; SO = Strikeouts
| Player | W | L | ERA | G | GS | SV | IP | H | R | ER | BB | SO |
| Nathan Eovaldi | 11 | 9 | 3.75 | 32 | 32 | 0 | 182.1 | 182 | 81 | 76 | 35 | 195 |
| Eduardo Rodríguez | 13 | 8 | 4.74 | 32 | 31 | 0 | 157.2 | 172 | 87 | 83 | 47 | 185 |
| Nick Pivetta | 9 | 8 | 4.53 | 31 | 30 | 1 | 155.0 | 137 | 80 | 78 | 65 | 175 |
| Garrett Richards | 7 | 8 | 4.87 | 40 | 22 | 3 | 136.2 | 158 | 86 | 74 | 60 | 115 |
| Martín Pérez | 7 | 8 | 4.74 | 36 | 22 | 0 | 114.0 | 136 | 71 | 60 | 36 | 97 |
| Garrett Whitlock | 8 | 4 | 1.96 | 46 | 0 | 2 | 73.1 | 64 | 22 | 16 | 17 | 81 |
| Tanner Houck | 1 | 5 | 3.52 | 18 | 13 | 1 | 69.0 | 57 | 32 | 27 | 21 | 87 |
| Adam Ottavino | 7 | 3 | 4.21 | 69 | 0 | 11 | 62.0 | 55 | 31 | 29 | 35 | 71 |
| Matt Barnes | 6 | 5 | 3.79 | 60 | 0 | 24 | 54.2 | 41 | 25 | 23 | 20 | 84 |
| Hirokazu Sawamura | 5 | 1 | 3.06 | 55 | 0 | 0 | 53.0 | 45 | 24 | 18 | 32 | 61 |
| Josh Taylor | 1 | 0 | 3.40 | 61 | 0 | 1 | 47.2 | 45 | 18 | 18 | 23 | 60 |
| Chris Sale | 5 | 1 | 3.16 | 9 | 9 | 0 | 42.2 | 45 | 19 | 15 | 12 | 52 |
| Darwinzon Hernández | 2 | 2 | 3.38 | 48 | 0 | 0 | 40.0 | 29 | 17 | 15 | 31 | 54 |
| Phillips Valdéz | 2 | 0 | 5.85 | 28 | 0 | 1 | 40.0 | 35 | 29 | 26 | 19 | 35 |
| Matt Andriese | 2 | 3 | 6.03 | 26 | 0 | 1 | 37.1 | 55 | 29 | 25 | 11 | 38 |
| Hansel Robles | 0 | 1 | 3.60 | 27 | 0 | 4 | 25.0 | 21 | 11 | 10 | 13 | 33 |
| Yacksel Ríos | 3 | 0 | 3.70 | 20 | 0 | 0 | 24.1 | 13 | 10 | 10 | 14 | 21 |
| Brandon Workman | 1 | 0 | 4.95 | 19 | 0 | 0 | 20.0 | 24 | 11 | 11 | 14 | 14 |
| Austin Davis | 1 | 1 | 4.86 | 19 | 0 | 0 | 16.2 | 18 | 10 | 9 | 7 | 17 |
| Austin Brice | 0 | 0 | 6.59 | 13 | 0 | 0 | 13.2 | 14 | 10 | 10 | 7 | 12 |
| Ryan Brasier | 1 | 1 | 1.50 | 13 | 0 | 0 | 12.0 | 12 | 5 | 2 | 4 | 9 |
| Ryan Weber | 0 | 0 | 17.47 | 1 | 0 | 0 | 5.2 | 13 | 11 | 11 | 2 | 7 |
| Brad Peacock | 0 | 1 | 15.19 | 2 | 1 | 0 | 5.1 | 6 | 9 | 9 | 3 | 3 |
| Michael Feliz | 0 | 0 | 3.38 | 4 | 0 | 0 | 5.1 | 4 | 2 | 2 | 1 | 5 |
| Stephen Gonsalves | 0 | 0 | 4.15 | 3 | 0 | 0 | 4.1 | 2 | 2 | 2 | 2 | 4 |
| Eduard Bazardo | 0 | 0 | 0.00 | 2 | 0 | 0 | 3.0 | 1 | 0 | 0 | 2 | 3 |
| Connor Seabold | 0 | 0 | 6.00 | 1 | 1 | 0 | 3.0 | 3 | 2 | 2 | 2 | 0 |
| John Schreiber | 0 | 0 | 3.00 | 1 | 0 | 0 | 3.0 | 4 | 1 | 1 | 1 | 5 |
| Brandon Brennan | 0 | 0 | 0.00 | 1 | 0 | 0 | 3.0 | 3 | 0 | 0 | 2 | 1 |
| Raynel Espinal | 0 | 0 | 9.00 | 1 | 0 | 0 | 2.0 | 2 | 2 | 2 | 1 | 0 |
| Kutter Crawford | 0 | 1 | 22.50 | 1 | 1 | 0 | 2.0 | 5 | 5 | 5 | 2 | 2 |
| Jonathan Araúz | 0 | 0 | 9.00 | 1 | 0 | 0 | 1.0 | 2 | 1 | 1 | 0 | 0 |
| Colten Brewer | 0 | 0 | 36.00 | 1 | 0 | 0 | 1.0 | 4 | 4 | 4 | 3 | 1 |
| Christian Arroyo | 0 | 0 | 0.00 | 1 | 0 | 0 | 1.0 | 1 | 2 | 0 | 1 | 0 |
| Marwin González | 0 | 0 | 0.00 | 1 | 0 | 0 | 1.0 | 0 | 0 | 0 | 0 | 0 |
| Kevin Plawecki | 0 | 0 | 0.00 | 1 | 0 | 0 | 1.0 | 0 | 0 | 0 | 0 | 0 |
| Kaleb Ort | 0 | 0 | 0.00 | 1 | 0 | 0 | 0.1 | 1 | 0 | 0 | 1 | 0 |
| Team Totals | 92 | 70 | 4.26 | 162 | 162 | 49 | 1419.0 | 1409 | 749 | 671 | 546 | 1527 |
Source:

### Postseason game log

Boston Red Sox 2021 Postseason Game Log (6–5) :
American League Wild Card Game vs. New York Yankees (1–0)
#/DateOpponentScoreWinLossSaveStadiumAttendanceSeriesBox/ Streak
1October 5Yankees6−2Eovaldi (1−0)Cole (0−1)—Fenway Park38,3241–0W1 :
American League Division Series vs. Tampa Bay Rays
(3–1)
#/DateOpponentScoreWinLossSaveStadiumAttendanceSeriesBox/ Streak
1October 7@ Rays0–5McClanahan (1−0)Rodríguez (0−1)—Tropicana Field27,4190–1L1
2October 8@ Rays14–6Houck (1−0)McHugh (0−1)—Tropicana Field37,6161–1W1
3October 10Rays6–4 (13)Pivetta (1−0)Patiño (0−1)—Fenway Park37,2242–1W2
4October 11Rays6–5Whitlock (1−0)Feyereisen (0−1)—Fenway Park38,4473–1W3 :
American League Championship Series vs. Houston Astros
(2–4)
#/DateOpponentScoreWinLossSaveStadiumAttendanceSeriesBox/ Streak
1October 15@ Astros4–5Stanek (1–0)Robles (0–1)Pressly (1)Minute Maid Park40,5340–1L1
2October 16@ Astros9–5Eovaldi (1−0)García (0–1)—Minute Maid Park41,4761–1W1
3October 18Astros12–3Rodríguez (1−0)Urquidy (0–1)—Fenway Park37,6032–1W2
4October 19Astros2–9Graveman (1–0)Eovaldi (1−1)—Fenway Park38,0102–2L1
5October 20Astros1–9Valdez (1–0)Sale (0–1)—Fenway Park37,5992–3L2
6October 22@ Astros0–5García (1–1)Eovaldi (1−2)—Minute Maid Park42,7182–4L3 :

### Grand slams

| No. | Date | Red Sox batter | H/A | Pitcher | Opposing team |
| 1 | June 16 | Christian Arroyo | Away | A. J. Minter | Atlanta Braves |
| 2 | July 19 | Hunter Renfroe | Away | Ross Stripling | Toronto Blue Jays |
| 3 | August 23 | Travis Shaw | Home | Dennis Santana | Texas Rangers |
| 4 | October 16† | J. D. Martinez | Away | Luis García | Houston Astros |
| 5 | October 16† | Rafael Devers | Away | Jake Odorizzi | Houston Astros |
| 6 | October 18† | Kyle Schwarber | Home | José Urquidy | Houston Astros |
† Postseason game

### Ejections

| No. | Date | Red Sox personnel | H/A | Opposing team |
| 1 | April 15 | Alex Cora | Away | Minnesota Twins |
| 2 | June 3 | Alex Cora | Away | Houston Astros |
| 3 | June 19 | Christian Arroyo | Away | Kansas City Royals |
| 4 | July 17 | Will Venable | Away | New York Yankees |
| 5 | July 17 | Kevin Plawecki | Away | New York Yankees |
Source:

## Roster
### MLB debuts

Red Sox players who made their MLB debuts during the 2021 regular season:
* April 2: Hirokazu Sawamura
* April 4: Garrett Whitlock
* April 14: Eduard Bazardo
* June 22: Connor Wong
* July 17: Jarren Duran
* August 30: Raynel Espinal
* September 1: Jack López
* September 5: Kutter Crawford
* September 11: Connor Seabold
* September 13: Kaleb Ort

### Transactions

Notable transactions of/for players on the 40-man roster during the 2021 regular season:
* On May 3, the team claimed pitcher Brandon Brennan off of waivers from the Seattle Mariners; Ryan Brasier was moved to the 60-day injured list.
* On May 21, the team added utility player Danny Santana to the 40-man roster and activated him; Austin Brice was designated for assignment.
* On June 3, the team added reliever Brandon Workman to the 40-man roster and activated him; Colten Brewer was designated for assignment.
* On June 14, the team acquired pitcher Yacksel Ríos from the Seattle Mariners for cash; Ryan Weber was designated for assignment. Weber was later claimed off of waivers by the Milwaukee Brewers.
* On July 16, the team promoted Jarren Duran from Triple-A to the active roster; Brice was again designated for assignment.
* On July 29, the team acquired outfielder Kyle Schwarber from the Washington Nationals in exchange for minor-league pitcher Aldo Ramirez; Workman was designated for assignment. Workman subsequently elected to become a free agent.
* On July 30, the day of the trade deadline, the team acquired two relief pitchers: Austin Davis from the Pittsburgh Pirates in exchange for Michael Chavis, and Hansel Robles from the Minnesota Twins for minor-league pitcher Alex Scherff, with minor-league outfielder Marcus Wilson designated for assignment in a corresponding move. Wilson was later claimed off of waivers by the Mariners.
* On August 13, the team activated Schwarber and designated Marwin González for assignment; González was released three days later.
* On August 15, the team claimed infielder Travis Shaw off of waivers from the Brewers.
* On August 17, reliever Matt Andriese was designated for assignment; he was released two days later.
Note: players not in the organization as of August 31 were ineligible for the postseason.
* On September 2, the team claimed utility player Taylor Motter off of waivers from the Colorado Rockies. He appeared in three games with the team, then was designated for assignment on September 7. He cleared waivers and was sent outright to Triple-A.
* On September 4, the team claimed pitcher Geoff Hartlieb off of waivers from the New York Mets. He was later designated for assignment, then sent outright to Triple-A Worcester after clearing waivers.
* On September 6, the team signed free agent infielder José Iglesias, who had previously played with the team during 2011–2013 and had been released on September 3 by the Los Angeles Angels.
* On October 21, the team designated outfielder Franchy Cordero for assignment; he cleared waivers and was sent outright to Triple-A four days later.

### Amateur draft

Boston had the fourth overall selection in the 2021 MLB draft, held July 11–13. The draft consisted of a total of 612 selections over 20 rounds. The Red Sox' first 10 selections are listed here. The deadline for the team to sign drafted players was August 1.
| Round | Pick | Player | Position | B/T | Class | School (sorts by state) | Signing date |
| 1 | 4 | Marcelo Mayer | SS | L/R | HS Sr. | Eastlake High School (CA) | July 22 |
| 2 | 40 | Jud Fabian | OF | R/L | 4YR Jr. | Florida | did not sign |
| 3 | 75 | Tyler McDonough | 2B | S/R | 4YR Jr. | NC State | July 22 |
| 4 | 105 | Elmer Rodriguez-Cruz | P | L/R | HS Sr. | Leadership Christian Academy (PR) | July 24 |
| 5 | 136 | Nathan Hickey | C | L/R | 4YR So. | Florida | August 1 |
| 6 | 166 | Daniel McElveny | UT | R/R | HS Sr. | Bonita Vista High School (CA) | July 24 |
| 7 | 196 | Wyatt Olds | P | R/R | 4YR Jr. | Oklahoma | July 24 |
| 8 | 226 | Hunter Dobbins | P | R/R | 4YR Jr. | Texas Tech | July 24 |
| 9 | 256 | Tyler Miller | 3B | L/R | 4YR Jr. | Auburn | July 24 |
| 10 | 286 | Matt Litwicki | P | R/R | 4YR Sr. | Indiana | July 15 |
Source:

## Awards and honors

| Recipient | Award | Date awarded |
| J. D. Martinez | AL Player of the Week (April 5–11) | April 12, 2021 |
| Matt Barnes | AL Reliever of the Month (April) | May 3, 2021 |
| Xander Bogaerts | All-Star Starting SS | July 1, 2021 |
| Rafael Devers | All-Star Starting 3B | July 1, 2021 |
| Matt Barnes | All-Star Relief P | July 4, 2021 |
| Nathan Eovaldi | All-Star Reserve P | July 4, 2021 |
| J. D. Martinez | All-Star Reserve DH | July 4, 2021 |
| Enrique Hernández | AL Player of the Week (July 19–25) | July 26, 2021 |
| Bobby Dalbec | AL Rookie of the Month (August) | September 2, 2021 |
| Xander Bogaerts | AL Silver Slugger Award SS | November 11, 2021 |
| Rafael Devers | AL Silver Slugger Award 3B | November 11, 2021 |
| Rafael Devers | All-MLB Team 3B (second team) | November 23, 2021 |
Hunter Renfroe was a finalist for both a Silver Slugger Award and a Gold Glove Award.
Devers, Bogaerts, and Eovaldi each received votes in American League MVP balloting, finishing in 11th, 13th, and 15th place, respectively.
Eovaldi finished in fourth place in American League Cy Young Award balloting.

## Farm system

Entering the 2021 season, the Red Sox' farm system underwent multiple changes:
* The Worcester Red Sox succeeded the Pawtucket Red Sox as the Triple-A affiliate.
* The Lowell Spinners were dropped as an affiliate, as part of a reduction of the total number of minor league teams affiliated with MLB.
* The Greenville Drive and Salem Red Sox swapped relative classification levels, with Greenville moving from Single-A to High-A, and Salem moving from Class A-Advanced to Low-A.
Additionally, as part of the MLB reorganization of the minor leagues, the composition and names of various leagues were changed.
Managers were named in late January.
For the All-Star Futures Game, held on the Sunday before the All-Star Game, Boston had two players selected for the American League squad, infielder Jeter Downs (Triple-A) and pitcher Brayan Bello (Double-A).
In baseball at the Summer Olympics, contested during July and August in Tokyo, several minor-league Red Sox players won medals: Triston Casas and Jack López were on the US team that won silver, while Denyi Reyes, Roldani Baldwin, and Johan Mieses were on the Dominican team that won bronze. Darren Fenster, the Red Sox' minor-league outfield and baserunning coordinator, served as third base coach for the US team.
| Level | Team | League | Division | Manager | Record | Notes |
| Triple-A | Worcester Red Sox | Triple-A East | Northeast | Billy McMillon | 66–52 (.559) 8–2 (.800) 74–54 (.578) | Base: 3rd of 6 in division, 7th of 20 in league "Final Stretch": 3rd of 30 in classification Overall: 3rd of 6 in division, 4th of 20 in league |
| Double-A | Portland Sea Dogs | Double-A Northeast | Northeast | Corey Wimberly | 67–47 (.588) | 2nd of 6 in division; 4th of 12 in league |
| High-A | Greenville Drive | High-A East | South | Iggy Suarez | 67–53 (.558) | 3rd of 7 in division; 4th of 12 in league |
| Low-A | Salem Red Sox | Low-A East | North | Luke Montz | 71–49 (.592) | 1st of 4 in division; 3rd of 12 in league |
| Rookie | FCL Red Sox | Florida Complex League | South | Tom Kotchman | 37–20 (.649) | 2nd of 8 in division; 5th of 18 in league |
| Rookie | DSL Red Sox Blue | Dominican Summer League | North | Ozzie Chavez | 38–20 (.655) | 1st of 8 in division; 3rd of 46 in league |
| Rookie | DSL Red Sox Red | Dominican Summer League | Northwest | Sandy Madera | 31–27 (.534) | 4th of 8 in division; 17th of 46 in league |
Source: